Genuine gem-stones, such as diamonds, sapphires, emeralds and the like are of considerable value and it is of considerable interest to provide means for the positive indentification of an individual gem. This is of value for the owner who purchases the specific gem and can thus be given a certificate identifying his gem; it is of importance in cases when a gem is lost or stolen, and such positive records of identification can be used in Court as proof of identification. It is likely that insurance companies will find much interest in positive means of identification of gem stones, and other further features of the invention will become apparent hereinafter. The identification pattern according to the invention ought to be included in the insurance file of each gemstone. When gems are offered through middle-men, the recorded identification pattern makes possible a positive identification of each gemstone. Certificates issued for certain gems ought to be in conjuction with record patterns.